Terminally unsaturated vinyl ester resins are the reaction product of a polyepoxide and about equivalent amounts of an ethylenically unsaturated monocarboxylic acid. Such resins possess a number of outstanding properties which account for their commercial acceptance in such areas as molding resins, corrosion resistant reinforced plastic pipe and other vessels, glass fiber laminates and the like. The resins are generally too viscous to be handled easily in most fabrication methods. As a result, it is commonplace to lower the viscosity of the composition by blending the vinyl ester resin with an ethylenically unsaturated diluent such as the esters of acrylic or methacrylic acid.
The separate preparation of the diluent requires isolation of the product and purification as by distillation. Also it is frequently necessary to preheat the viscous vinyl ester resin to be able to blend the diluent uniformly therein.